In the latest sign of renewed strain, China has harshly condemned Japan for allowing a group of exiled Uighur activists to hold a major conference in Tokyo this week. China considers the group, the World Uyghur Congress, an “anti-China separatist organization.” Calling it a private group, Tokyo says it won’t interfere with its activities.

In a signal of its dissatisfaction with Tokyo’s Uighur position, China failed to arrange a bilateral meeting between Premier Hu Jintao and Japanese Prime Minister Yoshihko Noda last Sunday in Beijing, where the two nations and South Korea agreed to start formal negotiations for a trilateral free-trade agreement. To the annoyance of Japanese officials, Mr. Hu did meet bilaterally with South Korean President Lee Myung-bak.

Then Tuesday came the abrupt cancellation of a scheduled meeting between Chinese Foreign Minister Yang Jiechi and the visiting Hiromasa Yonekura, head of Japan’s powerful Keidanren business lobby. Chinese officials didn’t have an immediate comment.

The exiled head of the World Uyghur Congress, Rebiya Kadeer told those assembled that Beijing’s policy of “forcible assimilation” was unacceptable in a modern democracy.

“The Chinese government says it is assimilating and eventually eliminating the Uighur people and other indigenous people… meanwhile China is becoming a global power,” she told the opening of the congress.

“We are peacefully struggling and hope the Chinese government will stop the repressing of Uighur people… and take political reforms to change their authoritarian rule.

China considers the WUC a “splittist” organisation and has condemned Japan’s issuing of a visa for Kadeer, who last visited the country in 2009.